It is well known in the art that printed circuit cards or boards are provided for supporting and interconnecting various electronic components mounted thereon. Printed circuit boards typically are made of a fiberglass sheet of plastic to conform to any size or shape. Conductive strips of material are coated on one side of the printed circuit board for interconnecting the electronic components mounted on the printed circuit board. The electronic components are mounted on the printed circuit board such that input and output terminals of the electronic components are connected to the strips of conductive material.
As known in the prior art, when constructing the physical attributes of an electronic device such as would be used in aerospace applications where space and weight are at a premium electronic, enclosure 10 is used as shown in FIGS. 1, 2, and 3. The electronic enclosure 10 includes an opening plate 12 fastened to a flange 14 on the back surface of the electronic enclosure 10 by fasteners 15 such as screws or the like.
The internal space of the enclosure 10 can be accessed by removing the opening plate 12 as shown in FIG. 2. The internal space of the electronic enclosure 10 includes a plurality of conventional guide rails 18 for guiding a printed circuit board 19 to a mounted position to engage connector 20. The guide rails 18 are mounted on the sides of the enclosure 10. The mounted position is accomplished by mounting the printed circuit boards 19 in the connectors 20 positioned on a mother board 22. A side view of the electronic enclosure 10 having mounted therein printed circuit boards 23 is shown in FIG. 3. Each printed circuit board 19 has mounted thereon a connector 24 which mates with connector 20.
The conventional guide rails 18 used in the electronic enclosure 10 of the installation shown in FIGS. 2 and 3 guides a printed circuit board 23 to the mounted position by permitting the manual sliding of the printed circuit board 23 along the complete length of the guide rails 18.
Due to the manner in which the printed circuit boards 23 are guided to the mounted position by the guide rails 18 of the electronic enclosure 10 efficient use of all available space in the enclosure 10 is not possible. Particularly, it is extremely difficult to install a printed circuit board 23 in a space 25 in the enclosure 10 directly behind the flange 14 due to the manner in which the printed circuit boards 23 are moved to a mounted position using the guide rails 18. In order for printed circuit boards to be installed in guide rails 18 the printed circuit board must be slid along the complete length of the guide rails 18. This manner of installation requires that enough space be available directly in front of the guide rails 18 so that the printed circuit board can be maneuvered into the guide rails 18 and slid to the mounted position along the complete length of the guide rails 18.
Thus, the space within the electronic enclosure 10 is not efficiently used in that the flange 14 causes great difficulty in the positioning of a printed circuit board 23 in the space 25 directly behind the flange 14 in the electronic enclosure 10. The space 25 behind the flange 14 of the electronic enclosure 10 can be described as a limited access area.
Apparatus which is capable of guiding a printed circuit board to the mounted position in a limited access area of an enclosure would offer the advantage of efficiently using the space within an enclosure when space is at a premium in, for example, aerospace applications. Thus, more printed circuit boards can be mounted in the electronic enclosures.
Various conventional printed circuit board guide apparatus have been proposed for guiding a printed circuit board to a mounted position. However, none of the conventional printed circuit board guide apparatus are directed to solving the problem of guiding printed circuit boards to a mounted position in a limited access area.
One proposed method of permitting a printed circuit board to occupy limited access areas in an electronic enclosure is by bolting a printed circuit board to the bottom of the electronic enclosure directly behind the flange of the electronic enclosure. However, such an installation would not permit easy removal of the printed circuit board for servicing. Further, such an installation would provide the opportunity for damage to either the print circuit board or to the connector in which the printed circuit board is mounted.
U.S. Pat. No. 4,821,149 issued on Apr 11, 1989, discloses a substrate (printed circuit board) mounting device for mounting an electrical substrate to a carrier substrate having a first pair of tabs each extending from a perimeter edge of the electrical substrate directly opposite to each other and a second pair of tabs located in a spaced relationship to the first pair of tabs. The second pair of tabs extend from a perimeter edge of the electrical substrate directly opposite each other. In the substrate mounting device of U.S. Pat. No. 4,821,149 first and second substrate guides are located in a spaced and parallel relationship to each other with each including a lower shelf with each lower shelf having a top and bottom surface wherein the bottom surface is mounted to the carrier substrate. Each of the substrate guides of U.S. Pat. No. 4,821,149 further includes a channel having an open end and a top guide and defined by a top surface and first and second drop guides. The first and second drop guides are located on the lower shelf top surface directly opposite the channel top surface. The drop guides include first and second tab receiving slots.
In the substrate mounting device disclosed by U.S. Pat. No. 4,821,149 installation of a substrate is performed by manually inserting the first and second pairs of tabs of the substrate into respective first and second substrate guide channels at respective channel open ends and manually pushing the substrate along the complete length of the channels riding between respective first and second drop guides and channel top surfaces until the substrate encounters a respective top guide. When the top guide is encountered the first pair of tabs and the second pair of tabs fall within respective first and second tab receiving slots.
Thus, as can be clearly seen the device disclosed by U.S. Pat. No. 4,821,149 operates very similar to the conventional printed circuit board guide rails shown in FIG. 2 wherein the printed circuit board must be pushed along the complete length of a channel of the guide rail to a mounted position. The device disclosed by U.S. Pat. No. 4,821,149 differs from the conventional printed circuit board guide rails 18 shown in FIG. 2 in that once a certain point is reached during the sliding of the printed circuit boards in the channels of the guide apparatus disclosed in U.S. Pat. No. 4,821,149 the printed circuit board is permitted to drop into receiving slots.
Thus being that the device disclosed by U.S. Pat. No. 4,821,149 guides a printed circuit board for a mounted position similar to the conventional guide rails 18 shown in FIG. 2, the device cannot be used in an area of limited access such as directly behind a flange in an electronic enclosure.
A further example of printed circuit board guide apparatus is disclosed by U.S. Pat No. 4,779,744 issued on Oct. 25, 1988. The guide apparatus disclosed by U.S. Pat. No. 4,779,744 guides a printed circuit board similar to the conventional printed circuit board guide rails shown in FIG. 2 and the guide apparatus disclosed by U.S. Pat. No. 4,821,149. Thus, the guide apparatus disclosed by U.S. Pat. No. 4,779,744 requires the manual pushing of a printed circuit board along the complete length of the channel of the guide rail.
Therefore, the apparatus disclosed by U.S. Pat. No. 4,779,744 cannot be used in a limited access area directly behind the flange of an electronic enclosure.